This peptide is histone H4 (1-25) with acetylation at Lys12 and Lys16 and monomethylation at Lys20, followed by a C-terminal GSGS linker and a biotinylated Lys. Monomethylation of histone H4 at Lys20 is associated with transcriptionally silent chromatin in higher eukaryotes. It has been shown that histone H4 is preferentially acetylated first at Lys16, then at Lys12. Diacetylated histone H4 has been shown to bind repressor protein TUP1. Acetylation of histone H4 also regulates heterochromatin formation by promoting the binding of bromodomains to p300 and transcription factor TAFII250 and inhibiting interactions with SIR3. Provided at >95% peptide purity, this peptide was dissolved in distilled water at 1 mg/ml and re-lyophilized to powder form.